/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

package org.mozilla.intl.chardet;

public abstract class nsPSMDetector {

  public static final int ALL = 0;
  public static final int JAPANESE = 1;
  public static final int CHINESE = 2;
  public static final int SIMPLIFIED_CHINESE = 3;
  public static final int TRADITIONAL_CHINESE = 4;
  public static final int KOREAN = 5;

  public static final int NO_OF_LANGUAGES = 6;
  public static final int MAX_VERIFIERS = 16;

  nsVerifier[] mVerifier;
  nsEUCStatistics[] mStatisticsData;

  nsEUCSampler mSampler = new nsEUCSampler();
  byte[] mState = new byte[MAX_VERIFIERS];
  int[] mItemIdx = new int[MAX_VERIFIERS];

  int mItems;
  int mClassItems;

  boolean mDone;
  boolean mRunSampler;
  boolean mClassRunSampler;

  public nsPSMDetector() {
    initVerifiers(nsPSMDetector.ALL);
    Reset();
  }

  public nsPSMDetector(int langFlag) {
    initVerifiers(langFlag);
    Reset();
  }

  public nsPSMDetector(int aItems, nsVerifier[] aVerifierSet,
                       nsEUCStatistics[] aStatisticsSet) {
    mClassRunSampler = (aStatisticsSet != null);
    mStatisticsData = aStatisticsSet;
    mVerifier = aVerifierSet;

    mClassItems = aItems;
    Reset();
  }


  public void Reset() {
    mRunSampler = mClassRunSampler;
    mDone = false;
    mItems = mClassItems;

    for (int i = 0; i < mItems; i++) {
      mState[i] = 0;
      mItemIdx[i] = i;
    }

    mSampler.Reset();
  }

  protected void initVerifiers(int currVerSet) {

    int idx = 0;
    int currVerifierSet;

    if (currVerSet >= 0 && currVerSet < NO_OF_LANGUAGES) {
      currVerifierSet = currVerSet;
    } else {
      currVerifierSet = nsPSMDetector.ALL;
    }

    mVerifier = null;
    mStatisticsData = null;

    if (currVerifierSet == nsPSMDetector.TRADITIONAL_CHINESE) {

      mVerifier = new nsVerifier[]{
          new nsUTF8Verifier(),
          new nsBIG5Verifier(),
          new nsISO2022CNVerifier(),
          new nsEUCTWVerifier(),
          new nsCP1252Verifier(),
          new nsUCS2BEVerifier(),
          new nsUCS2LEVerifier()
      };

      mStatisticsData = new nsEUCStatistics[]{
          null,
          new Big5Statistics(),
          null,
          new EUCTWStatistics(),
          null,
          null,
          null
      };
    }

    //==========================================================
    else if (currVerifierSet == nsPSMDetector.KOREAN) {

      mVerifier = new nsVerifier[]{
          new nsUTF8Verifier(),
          new nsEUCKRVerifier(),
          new nsISO2022KRVerifier(),
          new nsCP1252Verifier(),
          new nsUCS2BEVerifier(),
          new nsUCS2LEVerifier()
      };
    }

    //==========================================================
    else if (currVerifierSet == nsPSMDetector.SIMPLIFIED_CHINESE) {

      mVerifier = new nsVerifier[]{
          new nsUTF8Verifier(),
          new nsGB2312Verifier(),
          new nsGB18030Verifier(),
          new nsISO2022CNVerifier(),
          new nsHZVerifier(),
          new nsCP1252Verifier(),
          new nsUCS2BEVerifier(),
          new nsUCS2LEVerifier()
      };
    }

    //==========================================================
    else if (currVerifierSet == nsPSMDetector.JAPANESE) {

      mVerifier = new nsVerifier[]{
          new nsUTF8Verifier(),
          new nsSJISVerifier(),
          new nsEUCJPVerifier(),
          new nsISO2022JPVerifier(),
          new nsCP1252Verifier(),
          new nsUCS2BEVerifier(),
          new nsUCS2LEVerifier()
      };
    }
    //==========================================================
    else if (currVerifierSet == nsPSMDetector.CHINESE) {

      mVerifier = new nsVerifier[]{
          new nsUTF8Verifier(),
          new nsGB2312Verifier(),
          new nsGB18030Verifier(),
          new nsBIG5Verifier(),
          new nsISO2022CNVerifier(),
          new nsHZVerifier(),
          new nsEUCTWVerifier(),
          new nsCP1252Verifier(),
          new nsUCS2BEVerifier(),
          new nsUCS2LEVerifier()
      };

      mStatisticsData = new nsEUCStatistics[]{
          null,
          new GB2312Statistics(),
          null,
          new Big5Statistics(),
          null,
          null,
          new EUCTWStatistics(),
          null,
          null,
          null
      };
    }

    //==========================================================
    else if (currVerifierSet == nsPSMDetector.ALL) {

      mVerifier = new nsVerifier[]{
          new nsUTF8Verifier(),
          new nsSJISVerifier(),
          new nsEUCJPVerifier(),
          new nsISO2022JPVerifier(),
          new nsEUCKRVerifier(),
          new nsISO2022KRVerifier(),
          new nsBIG5Verifier(),
          new nsEUCTWVerifier(),
          new nsGB2312Verifier(),
          new nsGB18030Verifier(),
          new nsISO2022CNVerifier(),
          new nsHZVerifier(),
          new nsCP1252Verifier(),
          new nsUCS2BEVerifier(),
          new nsUCS2LEVerifier()
      };

      mStatisticsData = new nsEUCStatistics[]{
          null,
          null,
          new EUCJPStatistics(),
          null,
          new EUCKRStatistics(),
          null,
          new Big5Statistics(),
          new EUCTWStatistics(),
          new GB2312Statistics(),
          null,
          null,
          null,
          null,
          null,
          null
      };
    }

    mClassRunSampler = (mStatisticsData != null);
    mClassItems = mVerifier.length;

  }

  public abstract void Report(String charset);

  public boolean HandleData(byte[] aBuf, int len) {

    int i, j;
    byte b, st;

    for (i = 0; i < len; i++) {
      b = aBuf[i];

      for (j = 0; j < mItems; ) {
        st = nsVerifier.getNextState(mVerifier[mItemIdx[j]],
                                     b, mState[j]);
//if (st != 0)
//System.out.println( "state(0x" + Integer.toHexString(0xFF&b) +") =>"+ Integer.toHexString(st&0xFF)+ " " + mVerifier[mItemIdx[j]].charset());

        if (st == nsVerifier.eItsMe) {

//System.out.println( "eItsMe(0x" + Integer.toHexString(0xFF&b) +") =>"+ mVerifier[mItemIdx[j]].charset());

          Report(mVerifier[mItemIdx[j]].charset());
          mDone = true;
          return mDone;

        } else if (st == nsVerifier.eError) {

//System.out.println( "eNotMe(0x" + Integer.toHexString(0xFF&b) +") =>"+ mVerifier[mItemIdx[j]].charset());
          mItems--;
          if (j < mItems) {
            mItemIdx[j] = mItemIdx[mItems];
            mState[j] = mState[mItems];
          }

        } else {

          mState[j++] = st;

        }
      }

      if (mItems <= 1) {

        if (1 == mItems) {
          Report(mVerifier[mItemIdx[0]].charset());
        }
        mDone = true;
        return mDone;

      } else {

        int nonUCS2Num = 0;
        int nonUCS2Idx = 0;

        for (j = 0; j < mItems; j++) {
          if ((!(mVerifier[mItemIdx[j]].isUCS2())) &&
              (!(mVerifier[mItemIdx[j]].isUCS2()))) {
            nonUCS2Num++;
            nonUCS2Idx = j;
          }
        }

        if (1 == nonUCS2Num) {
          Report(mVerifier[mItemIdx[nonUCS2Idx]].charset());
          mDone = true;
          return mDone;
        }
      }


    } // End of for( i=0; i < len ...

    if (mRunSampler) {
      Sample(aBuf, len);
    }

    return mDone;
  }


  public void DataEnd() {

    if (mDone) {
      return;
    }

    if (mItems == 2) {
      if ("GB18030".equals(mVerifier[mItemIdx[0]].charset())) {
        Report(mVerifier[mItemIdx[1]].charset());
        mDone = true;
      } else if ("GB18030".equals(mVerifier[mItemIdx[1]].charset())) {
        Report(mVerifier[mItemIdx[0]].charset());
        mDone = true;
      }
    }

    if (mRunSampler) {
      Sample(null, 0, true);
    }
  }

  public void Sample(byte[] aBuf, int aLen) {
    Sample(aBuf, aLen, false);
  }

  public void Sample(byte[] aBuf, int aLen, boolean aLastChance) {
    int possibleCandidateNum = 0;
    int j;
    int eucNum = 0;

    for (j = 0; j < mItems; j++) {
      if (null != mStatisticsData[mItemIdx[j]]) {
        eucNum++;
      }
      if ((!mVerifier[mItemIdx[j]].isUCS2()) &&
          (!"GB18030".equals(mVerifier[mItemIdx[j]].charset()))) {
        possibleCandidateNum++;
      }
    }

    mRunSampler = (eucNum > 1);

    if (mRunSampler) {
      mRunSampler = mSampler.Sample(aBuf, aLen);
      if (((aLastChance && mSampler.GetSomeData()) ||
          mSampler.EnoughData())
          && (eucNum == possibleCandidateNum)) {
        mSampler.CalFreq();

        int bestIdx = -1;
        int eucCnt = 0;
        float bestScore = 0.0f;
        for (j = 0; j < mItems; j++) {
          if ((null != mStatisticsData[mItemIdx[j]]) &&
              (!"Big5".equals(mVerifier[mItemIdx[j]].charset()))) {
            float score = mSampler.GetScore(
                mStatisticsData[mItemIdx[j]].mFirstByteFreq(),
                mStatisticsData[mItemIdx[j]].mFirstByteWeight(),
                mStatisticsData[mItemIdx[j]].mSecondByteFreq(),
                mStatisticsData[mItemIdx[j]].mSecondByteWeight());
//System.out.println("FequencyScore("+mVerifier[mItemIdx[j]].charset()+")= "+ score);
            if ((0 == eucCnt++) || (bestScore > score)) {
              bestScore = score;
              bestIdx = j;
            } // if(( 0 == eucCnt++) || (bestScore > score ))
          } // if(null != ...)
        } // for
        if (bestIdx >= 0) {
          Report(mVerifier[mItemIdx[bestIdx]].charset());
          mDone = true;
        }
      } // if (eucNum == possibleCandidateNum)
    } // if(mRunSampler)
  }

  public String[] getProbableCharsets() {

    if (mItems <= 0) {
      String[] nomatch = new String[1];
      nomatch[0] = "nomatch";
      return nomatch;
    }

    String[] ret = new String[mItems];
    for (int i = 0; i < mItems; i++) {
      ret[i] = mVerifier[mItemIdx[i]].charset();
    }
    return ret;
  }

}
